Jamks robertson



(No Model.)

J. ROBERTSON.

METHOD OF AND MEANS FOR MAKING TUBES.

No. 416,014. Patented Nov. 26, 1889.

Ift-TI 1 a4 1 men F' mm FIG 7.. IB 5'.

My! 5555- A HJEHTU 6% UNITED STATES PATENT FFICE.

JAMES ROIHCR'ISON, ()l lllltlll lNGllAM, ENGLAND.

METHOD OF AND MEANS FOR MAKING TUBES.

SPECIFICATION forming part of Letters Patent No. 416,014, dated November 26, 1889.

Application filed uly 27, 1389. Serial No. 318,887. (No model-l Patented in England April 4, 1888, No. 5,018, and in Be gium March 14, 1889,110. 85,383.

To all whom it may concern:

lie it known that I, JAMEs ROBERTSON, of Birmingham, England, have invent-ed certain new and useful Improvements in the Method of and Means for Making and Drawing Out Tube-Blanks, Tubes, Tubular Articles, and ll'ollow Articles or Shells, (for which 'iritish Letters Patent were granted, No. 5,018, dated April 4, 1889, and Belgian patent, No. 85,383, dated March 14, 1989,) of which the following is a specification.

My invention relates, mainly, to the manufacture of seamless metal tube-blanks and tubes and like seamless metal tubular hollow articlessueh as boiler-dues, pipe-coupling rings or sockets, and broad rims of pulleys or rolls-and parallel and tapering articles such as for shot and shell; and it consists in certain improved means for manufacturing the same. It is no part of my invention to use an y of these new and improved means or apparatus for making tubes out of what is usually designated soft metals such as lead and tin-that have the distinguishing feature from other metals of not hardening by compression or by being hammered in a cold state.

My invention consists in a long tube-die of improved shape or form for making or producing tubes, or chiefly metal tube-blanks or short thick tubes, to be afterward shaped and drawn out to thinner or smaller sizes, or otherwise subsequently finished, (which I shall hereinafter designate as tube-blanks,) from solid billets of. metal made soft by heat, or chiefly'adaptcd for making tube-blanks of iron, steel, and copper when in a heated and soft or viscid state. For this purpose I form a metal matrix or cast iron or steel of a round and slightlytapering form internally, with a smooth sur face, its central part lengthwise of nearly the same internal diameter and tapering form as the external diameter of the heated billet of metal it is ii'itendedto be used for and about double the lengthsofythis billet, so that when the hot billet is put into this die from its wide end it sticks firmly about the center of the die lengthwise. The die for some purposes may be in halves lengthwise andjointed longitudinally, and be turned up extertube-die, by preference, of

nally, also, by preference, of a tapering form and fitted into a strong containing-castiug capable of standing great internal lateral pressure from the die, and this billet or heated soft mass of metal so placed in this die I cause to be pierced by a conical or sharp pointed or bulbous mandrel in cross-areaabout one-half of the internal area of the die, entered cent-rally in at the wide end of thedio by a guide fixed on its mouth or otherwise, and by great force, through the inter\-'ent ion of a strong stem -rod, 1' push this mandrel swiftly into the soft mass of metahwhioh, by reason of the internal tapering form of the die and correspondingly fitting and fixing action of the billet, produces sulficientlateral frictional and abutting hold to it in the die to prevent it being pushed forward bodily by the mandrel, and results in causing the most of the heated soft metal of the billet to extend and How out around and over the mandrel and its forcing stenrrod in the reverse direction of the inward motion of the mandrel and its stem-rod and in the form of a tube or tube-blank or shell pierced with a hole the size of the mandrel. the mandrel, when nearing the farthest end of the billet, stretching out the metal in the billet, thereafter forward in the die, continuously into a tube until it has passed entirely through the billet of metal, producing thereby from th s billet of soft metal a tube of the internal diameter of the mandrel used and of a tapering form externally corresponding to the degree of taper formed in the internal surface of the die, all so formed to be removed out oi the die as quickly as possible, so as to avoid injuring it by heat as much as possible. The internal tapering smooth surface of the die as used for heated soft metal is an important feature of my invention said form enabling said metal ingots to be pierced and converted into a tube by the conjoint-use of said tapering die and a pierciug-mainlrel, first, by the instant and unfailing binding of the billet in the tapering die lengthwise or endwise sufficiently to withstand the great forward force of the mandrel, so that the metal will not be pushed before the mandrel bodily, the billet having no support at its farthest or inner end; secondly, by the smooth tapered bore or sent die, supporting and fixing the metal of the billet at all points in succession opposite the position of the mandrel in its progress through the billet against the tend ency of the force of the mandrel .to break off the metal of the billet crosswise, found to be a great defect in my parallel long-tube die, as described in the specification of my British patent, N 0. 15,752, of 1884, and, thirdly and mainly, by allowing the heated soft metal of the billet to squirt or flow out freely past the mandrel from the smooth tapered surface of the die in the form of a tube, the latter in this way constantly diminishing in external diameter, and the metal in the die or tube, as it is being formed, constantly starting from a point of smaller diameter in the die than it has afterward to pass through in its passage outward, thereby sustaining little or no resistance by frictional cont-act with the die during the outward motion in the form of a tube.

The mandrel should be made to pass through the soft metal at about the. same speed as manaizeis are passed through lap-welded-iron tube-blanks when being weldednamely, about four feet per secondand, within certain limits, the larger the diameter of the tubes or tube-blanks the more practicable will this mode of making them become, as the greater the mass of the mandrel (which, by preference, I form of hard cast iron or steel) the less it is liable to be injured by heat. For the general proportionsay for the after drawing out and finishing a tube or shell of sufficient mass for making a steel tube of eight inches bore, one-quarter of an inch thick, and fifteen feet long-the tapering die should be about thirty-two inches long, and its internal diameters at its extreme ends should be about nine and one-fourth and ten and three-fourths inches, respectively. The metal billet should be about seventeen inches long and its diameter at its extreme end about nine and one-half and ien and one-fourth inches, respectively. The mandrel at its greatest diameter should be about eight and one-fourth inch =1 in diameter to form a tube-blank of this size in. this way about five feet long.

To operate mandrels as described, quick endwise reciprocatin g motion is required, and for all ordinar Y diameters of tubes a great degree of force is required. Any good mechanical means may be used for reciprocating the mandrel and stem-rod, and they may be reciprocated by the direct action of pistons actuated by steam, water, or other fluid in a steady or in a percussive way; but I prefer to use direct pressure from 'hyd raulic rams or pistons actuated by pumps or otherwise at high pressure and stored in an accun'iulator to produce quick action.

Throughout my explanation I designate a solid piece of metal, or one with a small central hole in it, to be operated upon, as also a thick cast or hammered ring of metal to be operated upon, a billet; a piece of metal partially formed into a tube and open at both ends, a tube-blank. A finished hollow article of a length double that of its diameter or longer and open at both ends I designate a tube-f a hollow article open at both ends and of a length more than once and less than twice its diameter, a tubular article, and a hollow article of a length more than twice its diameter with a closed end, a shell.

Referring to the accompanyingdrawings, forming a part of this specification, Figure l is a front elevation, Fig. 2 an after end elevation, and Fig. 3 a longitudinal section through the lines 1 .l in Fig.1, of my improved taper die, Fig. showing the piercingmandrel just before it enters the die. Fig. 4.- represents a longitudinal section showing the mandrel passed through the die and the tube formed by the conjoint action of the die and mandrel. Fig. 5 is a front end elevation of another form of the die. Fig. 6 is a rear end elevation, and Fig. 7 a longitndimil section, of the same, the mandrel being shown in l ig. 7 before it has entered the billet. Fig. 8 represents a plan View of one of the sections of the die shown in Figs. 5, ti, and 7; and. Fig. .i represents a section like Fig. 7, but showing the mandrel after it has passed through the die.

The same letters of reference indicate the same parts in all of the figures.

In the drawings, A represents my improved taper die, and l; represents a billet placed in the same.

D represents a piercing-mandrel ready to be pushed into the die and guided by the mandrel-guide C, all suited for making the smaller sizes of tube-blanks 13.

By preference the die A is formed of castiron. The internal surface of the die A requires to have a smooth surface, and it is in this example shown bored out with straight surfaces and to a taper or angle of ten degrees, which is a suitable angle or degree of taper for forming tube-blanks from solid billots of steel or iron heated to a soft viscid state, the degree of angle or degree of taper of the acting surface of the die requiring to be suited to the kind of metal and its temperature. Generally the softer the metal the greater is the degree of angle required to give the metal or billet sufficient frictional side support and hold to keep itfrom beingpushed forward bodily before the mandrel l) and to allow the metal of the billet to flow outward with sufficient freedom past and over the mandrel from the wider end of the die A.

A billet of steel 13 in the hot state described is shown in the die in Fig. 3, which billet is roughly formed by casting or other wise to enter and fill up the die A, as shown. After the billet is so placed in the die and guide 0, for guiding and entering the mandrel D centrally into the billet B at starting, is applied to the die, said guide consisting of an annular ring, by preference of steel,bored out internally to easily fit the diameter of the mandrel D and of such external diameter IOU at its inner end as to lit the i'nonth oi the billet seat of the die. The mandrel D for the smaller sizes of tube-blanks is formed, by preference, of steel and hardened and formed in one piece with its stem-rod l). The center line of the mandrel and its stem-rod D at starting is located by the guide exactly in line with the axis of the bored-out seat for the billet B in the die A, and the mandrel is thereafter pushed throng-lithe mass of soft steel to the position shown in Fig. l. The metal is by the displacing action of the mandrel made to flov outward over the bulb-mandrelD and its stein-died. D, and pushes out the guide 0 from itsseat and along the stem-rod D, as shown, the metal flowing in a direction opposite to the movement of the mandrel, as indicated by the arrows on the mandrel and on the tube-blank in Fig. 4:. The tube-blank and mandrel are afterward removed from the die for a fresh operation.

There is almost 'no tendency of the mandrel D to go off the center of the billet after it is centrally entered, the metal being always softest at its center, because the exterior of the billet is hardened by the cooling tendency of the die in contact therewith and by co1npression against the die by the pressure of the mandrel, these results tending to keep the mandrel central in the billet afterit has been centrally entered and making the annular mass of the steel thus formed of equal thickness and suitable for drawing out into a tube of equal thickness, as shown.

The action above described is preferably effected by moving inward the mandrel D and its stem-rod D and by the squirting-out action of the fore part of the lube-blank 15; but it is obvious that the same results may be produced by forcing the die as indicated by the arrows c c. The axial line of thedie and mandrel is preferably horizontal, but it may be vertical or at any suitable angle. The force required on the mandrel to pierce masses or billets of steel. in a viscid soft state-sueh as when heated to about the same degree usually required for welding iron and steel-requires a force of about twenty tons to the square inch of cross-section of the mandrel, and this strain will indicate generally the strength of die-stem rods and other parts'of the machine to be hereinafter shown as the best modes of carrying out my said invention.

Fig. 5 is a front end elevation, Fig. 6 an after end elevation, both as turned on their sides, and Fig: 7 a sectional plan, of another form of my taper-tube die A, the same being in this example formed in halves or sec tions 2 and 3. In this example two-thirds of the length of the acting-surface of the die is shown bored out to a smaller degree of angle than the remaining third, the latter being shown as only slightly larger in diameter at ts rear end than the mandrel D. To prevent he mandrel D from forcing forward thebilat B bodily in the die, the after part of the internal surface of the die is shown with a series of steps or shoulders A formed in it, as best shown by the internal plan. of the half-die A in Fig. 8. These shoulders are shown at the bottom cut in parallel to the axis of the die, so as to allow the tube-blank B after it is formed to be freely withdrawn from the die. 'IhisiQlJlQiSliQis-also shown as constructed in halvesonsections 2- and 3, having its external diameter turned up freely in a tapering form and placed in a strong containing-frame E, which is bored out internally to suit the external surface of the die.

The tapering form of the exterior of the die and its holder enables a small amount of force to move the die out of its seat in the container 1, so that its halves maybe opened out, if required, to allow the tube-blank B, when formed, to be more freely taken out. This provision for readily opening the die enables the shoulders A in. the die to be formed deeper than here shown to take a still greater hold of the billet B and more surely prevent it from being forced forward bodily by the mandrel. The sectional construction also enables collars or beads to be formed on the after end or at any other portion on the tube-blauk B for various purposes.

, The front end of the internal surface of the die can be made with so small a degree of taper as four degrees and yet allow the metal to flow back over the in wardly-thru st mandrel D, although to do this at this small degree of taper requires the application of a greater degree of force on the mandrel. The sectional construction of the die, however, enables the greater part of the tube-blank B to be formed nearly parallel on. its external diameter, as shown in Fig. i). For short dies suited for short tube-blanks the fore part of the die may be parallel altogether. It is also part of my invention to insert into the dies constructed as described a thin lining F of asbestus mill-board or other form or composition of refractory lubricating material by placing it in the front end of the die, or the part of the die where-the metal flows outward over the mandrel, said lining being roughly shaped to a tapering form to the size and shape of the part of the inner surface of the die it is intended to lubricate and inserted into the die before the billet B is inserted, as shown in Figs. 7 and 8; butinstead of this a liquid or semi-liquid composition of asbestus or other lubricant may be used-such as graphite-not wholly destructible by heat an d adapted to adhere to the surface of the die. A lubricant of this kind may be laid in. by a brush to serve this purpose on commencing each tube-blank-forining operation. The insertion of the asbestus mill-board F greatly preserves the smoothness of the internal surface of the die A, and also reduces the force necessary to squirt out the metal over the mandrel. The die is preferably enlarged to ioo ITO

compensate for the thickness of the linin g. Another improvementherein illustrated consists in keeping the die A cool by forming in the internal surface of the container E broad shallow channels E, by preference of a spiral form, to allow a flow of cold water over most of the external surface of the die, and thus keep it cool. 'lhese spiral channels E E are shown in section in Figs. 7 and 9 and with an inlet-water-pipe nipple E and outlet-waterpipe nipple E" for the circulation of the water. The container E is shown provided with strong stay-rod snugs E. In this example, also, the bulb-mandrel I) is shown with a bored-out socket D to receive a correspondingly-turned fitting reduced stem end l), formed in the stem-rod D. For the larger diameters of tube-blanks the mandrels are preferred to be made of cast-iron and the stem-rod must be accurately fitted to their abutting ends to stand the great pressure exerted on them.

The stem-rods D, to stand the necessary end pressure, should be made of the most rigid steel procurable.

Fig. 9 shows the form of the tube-blank 3 after the mandrel D forced through the billet B and die A. The tube-blanks made by the improved method and means hereinbefore described may be finished or drawn out into tubes by the apparatus shown in my application for Letters Patent of the United States filed February 26, 1889, Serial No. 301,286, or by any other suitable apparatus or means.

I claim- 1. As an improvement in apparatus for making and drawing out tube-blanks, tubes, tubular articles, and hollow articles or shells from billets of metal, the combination of a die having a tapering bore orseat, a mandrel formed to pass through said bore or seat, said mandrel having a piercing end formed to penetrate said billet, and means for forcing the mandrel into the billet, whereby the material of the latter is caused to exude from the die around the mandrel in the form of a tube which is larger than the mandrel, as set forth.

2. As an improvement in apparatus for making and drawing out tube-blanks, tubes, tubular articles, and hollow articles or shells from billets of metal, the combination of a die having an internal bore or seat, a piercing-mandrel formed to pass longitudinally through said seat, and a guide coi'nposed of a ring removably inserted in one end of the die. whereby the mandrel is centrally entered intc a billet in said die.

23. A die having a smooth internal bore 01 seat of tapering form, which is prov-'i-t'led at its smaller end with steps or shoulders whereby a billet or blank placed in the die it supported against the pressure of a mandrel combined with a piercing-mandrel formed t pass through said billet and means for fore ing the mandrel into the Slll'lDOll'Gtl billet. a: setforth.

4:- The combination of a tube-forming llll having a tapering bore or seat, a piercing mandrel formed to penetrate a billet in sait bore or seat and thereby cause the materia of the billet to exude from the die in tubnla form, and a lubricating lining of refractor material covering suitable portions of sai seat, whereby the friction of the exuding ma terial on the said bore or seat is reduced, a set forth.

5. The improved method of making art drawing out tube-blanks, tuln's iniar art cles, and hollow articles or she. ereinln fore described, the same consisting in su porting the periphery of a billet against 101 gitudinal pressure in a smooth-surfaced t: pered die and piercing the billet .iongit-ud nally, thus causing the metal of the billet t squirt or [low out from the larger end of th die in the form of a tube and separate fro: the surface of the die as fast as the tube formed, as set forth.

In testimony whereof I have signed in name to this specification, in the presence two subscribing witnesses, this list day May, 1880.

JAMES R0 l) lCR'lSt.) N. 

